Solution for treatment of fibrous cellulosic materials



Patented Nov. 3, 1953 l'lED STATES er OFFICE SOLUTION FOR TREATMENT OF FIBROUS CELLULOSIC MATERIALS of New Jersey No Drawing. Application May 31, 1951, Serial No. 229,272

Claims. (Cl. 106-15) This invention relates to treated cellulosic material, and is a continuation-in-part of our copending application Serial No. 134,342, filed December 21, 1949, now abandoned. More specifically it relates to fire resistant material. Still more specifically it relates to flame resistant, cellulosic materials and a method'for their production,

Many types of agents have been proposed for rendering cloth, paper and other fibrous mate rials fire resistant, and some have been successfully employed, but few have the necessary properties to be able to withstand the rigors of handling and cleaning, particularly of washing and laundering. Some of the known treating agents are capable of being washed and laundered to a limited degree, but most of them appreciably alter the appearance, texture or tensile strength of the treated cellulosic material. In addition many of the known agents are not sufiiciently adherent and tend to separate from the treated material in the form of fine dust.

Among the fire retarding agents which are non-launderable are the phosphate, borate and sulfamate types. Launderable types of agent include resins, chlorinated resins, or waxes added in combination with inorganic oxides such as antimony oxide. They, however, have the disadvantage of altering the appearance of the material considerably, and that they must be added in large quantity. Titanium has been added in several fire resistant processes, but in most of these the titanium has been added as titanium dioxide in order to obtain opaque pigment efiects.

An object of this invention is, therefore, to provide an agent useful in the treating of fibrous cellulosic materials to render the same fire resistant. Another object is to provide an agent for the treatment of fibrous cellulosic materials to impart fiameand glow-resistant properties thereto which will not be affected by washing or laundering. A still further object is to provide a solution for the treatment of fibrous cellulosic materials to render the same fire resistant, which will not alter the appearance, texture. or tensile strength of the material. A further object is to produce fire resistant fibrous cellulosic materials in which the appearance, texture and tensile strength of the materials have not been altered by the treating agent. These and other objects of the present invention will become apparent as the invention is more fully described.

In its broadest aspects this invention contemplates production of a fire resistant or non- I inflammable fibrous cellulosic material by imand the like.

pregnating the material with an aqueous solution of titanium chloride acylate which is capable of forming a transparent gel, gelatinizing said solution on said material to form a transparent gel, alkalizing said gel-containing material with an alkaline neutralizing agent and subsequently washing and drying said material. For improved flame resistance together with resistance to afterglow, the above process may be carried out using an aqueous solution of titanium chloride acylate which contains antimony chloride, and this improved process is also contemplated by this invention. This invention further contemplates fibrous cellulosic materials which have been rendered flame resistant by the present process.

A titanium salt solution useful in the practice of this invention for treatment of fibrous cellulosic material to impart fire resistance thereto comprises an aqueous solution of titanium chloride acylate. The solution may also contain antimony chloride for improved and superior results. The titanium chloride acylates are derivatives of orthotitanic acid, Ti(OH) 4, in which some of the hydroxyl groups of the orthotitanic acid have been replaced by chloride ions, and others have been replaced by acylate groups. An acylate group, as used here, is understood to mean a derivative of a carboxylic acid obtained by removal of the carboxyl hydrogen of the acid.

It has been found that satisfactory results are obtained when the titanium concentration "in the aqueous solution of titanium chloride acylate-is between 40 and 150 grams per liter, preferably about grams per liter,- the concentration of chloride may be from 0.75 to 2.25 parts for each part of the titanium, and the concentration of acylate from 1.25 to 3.70 parts for each part of titanium. When antimony chloride is used the concentration of antimony may be from 1.0 to 3.0 parts for each part of titanium, and an' additional amount of chloride should be present to form antimony trichloride. The chloride values in the antimony chloride are in addition to the chloride values of the titanium chloride acylate.

Among the fibrous cellulosic materials which may be rendered fire resistant by the process of the instant invention are fabrics such as cotton, linen, regenerated cellulose, viscose and cellulose acetate, also natural fibers such as kapok, hemp, wood and wood products such as pressed boards, cardboard, batting, paper, wood flour, sawdust, The cellulosic material is treated with the titanium salt solution by any convenient means, such as by dipping the materialin 3 the solution, or by spraying the solution on the material. Any excess solution on the cellulosic material may be removed, for example, by squeezing between rolls, deliquoring in, alfiltfir pre or anyother' appropriate methodldepending upon 5 the physical nature of the material. It is preferred to leave a quantity of solution on the ma,- terial about equal to the weight of the material itself, 1. e. a weight pick-up f abo1it10( t%. ii/The titanium salt solution impregnated in the cellulosic material is gelatinized, i t ,examplebyexposing the treated material t, V v tnitispn a short interval of time satis factory gresults have been obtained when the exposure is such as to reduce the weight of solution,held by the cellulosic material to about to of its weight. The cellulosic material containing the gelatinized treating agent is then subiectedgto an alkalizing agent in :order to raise the pH of the treated material to abovem'lfi, pre e ably tabove 9.Q.-ibut. .not exceeding about llfi, The type .of talkalizing agentused is: unimportant al- +-though-,-weak alkalizin agentsrsuchQas, nex- -;a-mple-,- sodium carbonate or ammonium ox- -:i de orcarbonataare pneierred. fl' hematerialiis 2 Ithenirinsedwell with water for example; de- -.cantati0n,.;.in order torre nove lthe soluble salts therefrom and; subsequently d ried. "1

ed a ot: impregnant on' thelfinalamaterial ;(dr .is about 6,0 to 9.0% of the weightothafibrous V ,cellu-losic; material --.when the titanium chloride Qacylate solution lisgused; alone, while about-14% -..to.. l 6i%, is preferredgrwhen -the :combination.= bfutitanium chloride acylate and antimony chloride is employed g 1t,has .-been-found that thehpreferr p tkc'la'rr'iajifllit room mnerature although, desired, temperatures to 60..-.C..may beemployea v s rThelentire-proc s V ,rl'rhef exact naturelof thefpl ysica changes,-that ta1-:e place during thisrprocessis not om may :understood:. However,- the'; solution .fdgatitanium chloride aeylate is 1 apparently conever ci ously.i to\ the cellu l'osic lmateri l and; is ;not r emoved by-esubsequent was hingt, it may be, held .lih; the are or, between the fibers of ,thecellulosic material,;may;vbe absorbedlo'i; ladsorlqedpn T-thesurfacepr niayreact to some extent with the ellulo'sic'materialiitself. I

To illustrate preferred embodiments. .etgthis invention, the following examples are presented:

Inorderstozprepare an aqueous solutionoifti- 5 ==taniumchloride acetate the following procedure Was used:-,. l. -i 1.. '35.;

Two: parts .oflead=acetate -(Pb.(C2HsOz)=2;3I-Ii O) were dissolved in =,-on,e;part. of .waterv .loyl-weight "at-165Ch Thelead;acetatesolution was addedeo V slowly to a' solution of,titaniumrtetrachloride, containing? 1180- grams per; liter titaniums 1 flhe .aamountof lead-acetate solution; used was; .quivtalent: to react -with: of; the, chloride ,values epresent in the titanium tetrachloride;,s0lution." 5 The time of addition of the lead-acetate solutionnto the titanium tetrachloride wasxzghours inf'ord'n tojmai'ritain the. temperatureof the mixture below 25"v C. The'mix'ture wasthen. filtered to remove th'elead' chloride'froi'n "the titanium"7 loride' a'cetatesolution. The titanium chloride ac'et tained 77 gr'ains -per-1iter of titanium, 262'grams liter of acetate, em.

and grams'per liter chlo- Y QQ JiS 30 v l 1 a 117- 1 19, Re

tedlto .a' transparent vgelwhich; adherestenav The titanium chloride acetate solution was diluted with water to produce a solution containing 60 grams per liter titanium. This so-- ut ntwas n sdr t e insaclgth "t 010th W cotton twill weighing "8.2 ounces"per square 'yard.

The cloth was immersed in the solution for "2 minutes and was passed through a hand Awringer .Theco'peration was repeated the sechind tim'e (immersed and wrung again) to obt ;The treated cloth was then exposing the cloth to the at- Qsph, e urs to gelatinize the treating agen ncgthe aflcloth. The gelatinized treated cloth was thenjmmersed for 5 minutes in a so- "tion ofsodiiim hydroxide containing 200 g. p.

" l NaOI-I to alkalize the solution retained on the then was carried out 1 at Q room te'inpe'r'atu narra i n-Twa sumeaedm ne dd in 'Tabl test and the results are recor and s 1:10am Qu onjftolforma treating/solut o was asi'ali alkalizf I g u I Theftfreated 1: t

.a hell s an ard, time t 'sults are recorded in Table I.

"Table 'I iiqgzia mplel v i t eat d with, a. ib t 1 ii ace e w en used si als): 99 ni tion with antimony chloride; "and"'wh en"used in combination with the antimony chloride the cloth also exhibits glow resistant properties.

A third portion of the titanium chloride acetate solution used in Example I was diluted to 60 grams per liter titanium and used for treating wood flour. i

The wood flour was immersed in the solution and agitated for minutes to insure thorough soaking. The excess solution was separated from the wood flour by deliquoring on a filter press. The filter cake was then removed from the press and partially dried by 3 hours exposure to the atmosphere to gelatinize the solution on the wood flour. This treated. partially-dried wood flour was then immersed in a solution of 150 grams per liter NazCoa and agitated for 10 minutes to alkalize the solution on the wood flour, and again deliquored. The pH of the retained solution in the wood flour was 9.8. The wood flour was then thoroughly washed in water until the pH of the retained solution was 7.8 and dried. The treated wood fiour was tested for flame retardation by holding in the flame of a Bunsen burner for several seconds. It was observed to char only and did not flame. Untreated wood flour when tested similarly flamed immediately and was almost entirely consumed.

While the examples shown illustrate employment of titanium chloride acetate solution, which is preferred, solutions of titanium chloride formate and titanium chloride propionate may be used with similar efiect. These compounds, however, are somewhat more expensive to produce and therefore not as economical as the acetate salt.

By means of the present invention it also has been found that fibrous cellulosic material treated with the titanium chloride acylate solution retains flame resistance after laundering. The laundering is carried out in a tumbling chamber with 0.5% neutral soap solution at 70 C. However, when the preferred method of this invention is employed, utilizing the combination of titanium and antimony compounds as described, the superior flame and glow resistance characteristics are retained even after repeated laundering. After 6 launderings, for instance, the results are identical to those before launderi These results are compared in Table H with a well-known treating agent which consists of a mixture of borax, boric acid, and diammonium hydrogen phosphate.

Table II After- 011 ed After Aitergow launderflame f g h 258 mg (896') area. (sec.)

Ti-chloride-acetate ltime... 25 60 10.4 Ti-chloride-acetate+antldo- 0 0 4.5

mony chloride. '1i-chlorlgileigcetate+anti- 6tlmes. 0 0 4.5

men 0 or e. Boraxyboric acid, and (11- ltime ammonium hydrogen phosphate.

1 Completely burned.

A fibrous cellulosic material treated with a solution of titanium chloride acetate retains a useful measure of flame resistant properties upon laundering. However, when the cellulosic material is treated with the combination of agents, that of .a solution of titanium chloride acetate and antimony chloride, the flame and glow resistant characteristics are maintained after repeated laundering. The combination of agents apparently produces a synergistic efiect which enhances the flame resistance as well asimparting glow resistance and results in retention of these characteristics after laundering. The agents employed are fixed by employment of the process of this invention and are rendered durable toward washing.

Recoveries of both titanium and antimony values are substantially per cent during processing. The amounts of titanium and antimony originally absorbed on the fibrous cellulosic material are equal to the amounts retained in the final material after processing.

When the titanium values are present in the material in substantially opaque form, the treated material has an unpleasant white tone and a white dust may be continually removed from the surface. By the utilization of the process of this invention, however, the titanium values are fixed in the material in a form in which substantially no alteration in appearance or texture of the material is observed. The. treatment process is simple, convenient and economical to use. By employment of this invention, fibrous cellulosic materials may be treated to render them permanently resistant to fire.

While this invention has been described and; illustrated by the examples shown, it is not intended to be strictly limited thereto and other modifications and variations may be employed within the scope of the following claims.

We claim:

1. A solution for treatment of fibrous cellulosic materials to impart fire resistance thereto comprising an aqueous solution of titanium chloride acylate, said acylate selected from the group consisting of formate, acetate and propionate, the titanium of said titanium chloride acylate being present in concentration from 40 to grams per liter, the acylate group of said titanium chloride acylate being present in amount from 1. 5 to 3.70 parts for each part of titanium present, the chloride of said titanium chloride acylate being present from 0.75 to 2.25 parts for each part of titanium present.

2. A solution according to claim 1 in which said acylate is acetate.

3. Solution according to claim 1 in which said acylate is formate.

4. Solution according to claim 1 in which said acylate is propionate.

5. A solution for treatment of fibrous cellulosic material to impart fire resistance thereto comprising an aqueous solution of titanium chloride acylate and antimony trichloride, said acylate selected from a group consisting of formate, acetate and propionate, the titanium of said titanium chloride acylate being present in concentration of 40 to 150 grams per liter, the acylate group of said titanium chloride acylate being present in amount from 1.25 to 3.70 parts for each part of titanium, the antimony of said antimony trichloride being present in amount from 1.9 to 5.75 parts for each part of titanium, the chloride of said titanium chloride acylate being present in amount from 0.75 to 2.25 parts 

1. A SOLUTION FOR TREATMENT OF FIBROUS CELLULOSIC MATERIALS TO IMPART FIRE RESISTANCE THERETO COMPRISING AN AQUEOUS SOLUTION OF TITANIUM CHLORIDE ACYLATE, SAID ACYLATE SELECTED FROM THE GROUP CONSISTING OF FORMATE, ACETATE AND PROPIONATE, THE TITANIUM OF SAID TITANIUM CHLORIDE ACYLATE BEING PRESENT IN CONCENTRATION FROM 40 TO 150 GRAMS PER LITER, THE ACYLATE GROUP OF SAID TITANIUM CHLORIDE ACYLATE BEING PRESENT IN AMOUNT FROM 1.25 TO 3.70 PARTS FOR EACH PART OF TITANIUM PRESENT, THE CHLORIDE OF SAID TITANIUM CHLORIDE ACYLATE BEING PRESENT FROM 0.75 TO 2.25 PARTS FOR EACH PART OF TITANIUM PRESENT. 